This invention relates to an automatic cartridge tape draw-out device.
In recent years, there has been a trend toward housing microfilm, magnetic tape, movie film and other information recording media in tape-form in cartridges in order to facilitate handling, transportation and storage thereof. With this trend, it has become necessary to solve problems involving automatic loading and automatic threading of tapes in various equipment utilizing cartridge tapes, such as microfilm readers, magnetic recording and reproducing apparatus, movie cameras, projectors and the like.
Generally, cartridge type tapes are wound on a reel which is housed in a cartridge and is completely enclosed in the cartridge. Thus, it is desirable to provide means for automatically drawing out the leading end of the tape from the cartridge, and for automatically feeding it to a take up reel.
One type of automatic cartridge tape draw-out device is illustrated in FIG. 1 and comprises a reel drive roller 602, adapted to engage with reel flanges 601a and 601b, and a tape draw-out roller 603 of a diameter larger than the diameter of the reel drive roller 602 and adapted to move between the flanges 601a and 601b to engage the tape 605. The rollers 602 and 603 are rotably mounted coaxially on a common shaft 604 to rotate as a unit. In this type of devices the tape 605 wound on the reel is gradually loosened as the reel flanges rotate in the direction of an arrow b as they are driven by the reel drive roller 602 rotating in the direction of an arrow a. The loosened tape is drawn out by centrifugal forces till a leading end 605a of the tape is brought into engagement with the tape draw-out roller 603. Since the reel drive roller 602 and reel draw-out roller 603 rotate at different peripheral speeds, the leading end 605a of the tape is withdrawn from the cartridge as indicated by an arrow c.
The use of such automatic cartridge tape draw-out device offers the advantage of permitting the tape to be drawn out smoothly by a simple mechanism. However, it has been found that, because the peripheral surface of the tape draw-out roller 603 is planar, the leading end 605a of the drawn-out tape tends to slip against the roller 603 when it is brought to a position shown in FIG. 2, thereby preventing the tape from being smoothly withdrawn from the cartridge.
After the leading end 605a of the tape 605 is drawn out from the cartridge, it is generally fed to a tape advance means shown in FIG. 3 as comprising a capstan roller 606 and a pinch roller 607 pressing against each other to advance the tape toward a projection section.
One of the problems raised in advancing the tape in this way is with the criticality of the angle formed by the leading end 605a of the tape moving toward the capstan rollers and pinch rollers 606 and 607 with the line connecting the centers of the two rollers. That is, the smaller the angle, the more difficult it becomes for the leading end of the tape to be pinched by the two rollers 606 and 607, with the result that one or more convolutions of the drawn-out tape move idly in front of the tape advance means.
When the peripheral surfaces of the two rollers 606 and 607 are planar, the path of movement of the leading end 605a of the tape is perferably perpendicular to the line connecting shafts 606a and 607a of the two rollers. If the angle formed by the path of movement of the leading end of the tape and the line connecting the two shafts is too acute, difficulty is experienced in having the tape pinched by the two rollers 606 and 607.
A device of the type discussed above is disclosed in U.S. Pat. No. 3,704,836 issued to the inventor in the subject patent applications and assigned to the same assignee.